Arrangement for automatically regulating the voltage of dynamos



L. SCHON.

ARRANGEMENT FOR AUTOMATICALLY REGULATING THE VOLTAGE 0F DYNAMOS. APPLICATION FILED DEC. 23, 1913. RENEWED FEB. 21, 1920.

1,352,839. Patented p 14,1920.

I 3M 5 I 7 fl/E/LWII MW UNITED STATES P T NT omen.

LUDWIG SCHfiN', O-F ESSEN-ON-THE-RUHR, GERMANY, ASSIGNOB- T FRIED KRU'P]? AKTIENGESELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

ABRANGEMENT FOR AUTOMATICALLY REGULATING THE VOLTAGE OF DYNAMOS.

. Application filed December 23,1913, Serial No. 808,470. Renewed February 27, 1920. Serial No. 361,719.

To all whom it may concern:

Be it known that I, Dr. LUDWIG SorroN, residing at Essen-on-the-Ruhr, Germany, a

' subject of the Emperor of Germany, have inviding the auxiliary voltages, such as ae--' cumulator batteries or the like, which automatically deliver a constant voltage, cannot be procured, as for instance; is the case on board ship. g

In the accompanying'drawing is illustrated one embodiment of this invention, and V Figure 1 shows a diagrammatic representation of the arrangement;

Fig. 2 a diagram representing the manner of operation, and Fig. 3 a diagrammatic view of anauxiliary exciting winding.

A denotes the armature of a dynamo rep resented as shunt generator, and a an auxil iary exciting winding which may be arranged either on the magnet stand of the generator itself or on a separate exciting machine as in Fig. 3. In order to simplify the drawing it has been supposed that the wind ing a is situated on the field-frame of the generator itself; The winding a is fed by a small constantly excited auxiliary generator B (for example through permanent magnets), which auxiliary generator is connected, through the exciting winding m in o position to the armature of the generator .The winding a is wound in such a manner, that the current, flowing in the exciting circuit B A a from the positive terminal of I the auxiliary generator B toward the posierator. For driving the auxiliary generator tive terminal of the main generator A, causes a-strengthening of the field of the main gen- B, a shunt motor C is provided which is connected with the terminals of the main generator A. The common shaft D of the motor E. pear in the exciting circuit B A a which- C and the auxiliary generator B carries a fly wheel E. The relations have been so selected that the auxiliary generator B delivers voltage which is equal to the normal voltage of the main generator A, with the number of revolutions which the motor C Patented Sept. 14, 1920.

makes during normal voltage of the machine.

The described connection operates in the following manner:

As long as the terminal voltage E of the main generator A has its normal value and the terminal voltage E, of the auxiliary generator in consequence has the same value, the windinga has no current on account of the generators B and A being connected in opposition to each other. As soon, however, as the least difference appears between the voltages E.1 and E, an equalizing current will flow through the winding a which current runs in the direction of removing the diflerenc'e between the voltage E and E Should, for instance, the voltage E decrease, in consequence of a sudden increase in load, then the voltage E will at first retain its normal value as the number of revolutions of the auxiliary generator B, remains at first practically unchanged in consequence of the action of the fly wheel A compensating current will then apcurrent fiows through the exciting winding a in such a direction that it causes a rising of the field strength and consequently also of the voltage of the generator A. Directly after the appearance of the disturbance, which causes diminution of voltage of the generator, a regulation will occur which works in opposition to this diminution of voltage. Should the disturbance be of only short duration there will be no noticeable change in the number of revolutions of the generator B, and as a consequence a normal condition will therefore very rapidly appear after the disturbance has ceased. The operation takes place in similar manner when there is a disturbance which works in the direction of an increase of the voltage E,.

If disturbances of longer duration occur, the fly wheel E no longer has the power to keep the numbenof revolutions of the auxiliary generator B practically constant. The proceeding in such a case will be explained by means of the 'diagram given in Fig. 2. In this case the line 0 (t denotes thevoltage characteristic of the main generatorA, rela ,tive to the common number of revolutions n of the motor C, and the auxiliary gener-.

ator B; and the line 0 b the voltage characteristic of the generator B also relative to the number of revolutions n. The characteristic o b isa straight line when the auxiliary generator B is constantly excited; the characteristic 0 a is a curve bent convexly against the abscissa axis when the motor C is a shunt motor. The abscissa o c of the intersecting point (i of the two characteristics, represents the number of revolutions 1: existing during normal conditions in which the voltage of the generator A, represented by the ordinate 0 d, has the same value as the voltage of the auxiliary generator B.

' It will now be supposed that a disturbance occurs which would cause a. diminution of the voltage E to the value c e if the excitingwinding m was disconnected. The number of revolutions n will then diminish 'to the value which is represented by the abscissa "0 f of that point 9 of the characteristic 0 a, the ordinate of which is equal to 0 e. The voltage E will then have the value f h. This value is greater than the value] 9 to which the voltage E has dropped in consequence of. the condition that the characteristic 0 a is convexly curved relative to the abscissa axis. If we now suppose that the exciting winding a is connected in order to agree with the actual conditions, there will therefore appear in said winding a compensatin current which will cause an increase of t e value of E,,. By longer duration of the disturbance. a condition of equilibrium will now occur, in which case the following conditions will obtain, namely the numberof revolutions nzo i and the voltage E i is and E =i m. In order to create a condition of equilibrium, the difference'in voltage E 'E;=m 70 has to be just so large that it generates in the winding a a current, which is able to create voltage increase 72. nzi k/'' g, which the generator A had received. It might now be supposed in the first approximation that the voltage increase is n is proportional with the exciting current and therefore also with the voltage difi'erence m k. The values m is and is 'n will then be in constant relation, which is determined by the magnetic. characteristic of the exciting windlng a fore be determined as point ofmintersection of the characteristic 0 a andoa straight line e n g and-the straight line 0 b. As may be seen directly from the diagram, the value 2' is whichthe voltage E will have during the condition of equilibrium will As will now be evident, the point may there approach its normal value a a? so much closer, the nearer the point g is situated to the point all; that means the smaller the ratio is between the voltage diflerence E E delivered by the exciting current, and the hereby generated voltage increase of the generator A.' For this reason the exciting winding a should not be arranged directly on the field frame of the generator A as has been representedin thedrawing for sake of simplicity, but preferably on a special exciting machine see Fig. 3. It will moreover be evident from the diagram that it is advantageous to select the ratio in such a manner that the characteristic 0 a runs as steep as possible near the point (i.

condition. This, however, need not be the case if it is considered significant only to have quick reestablishm'ent of the normal voltage during disturbances which are of only short duration. In this case it is onl of importance apart from the fly wheel B that the auxiliary generator B possesses thequality to deliver a constant voltage with a constant number of revolutions.

I claim:

1. Arrangement for automatically regulating the voltage of a dynamo comprising a shunt winding and an auxiliary exciting winding for said dynamo, which winding is normally inoperative and: only rendered operative when the voltage of said dynamo varies; a generator constituting an auxiliary source ofvoltage practically independent of the load of said generator, the armature of said generator being connected in opposition to the armature of said dynamo through i said excitlng winding, and an electric motor.

for driving said motor being fed by for constantly exciting said auxiliary generator. 2. Arrangement for automatically regulating the voltage of a dynamo comprisgienerator, said electric .ing a shunt windlng andan auxiliary exciting winding for said dynamo, v which winding is normally inoperative and. only rendered operative when the voltage of said dynamo varies; a generator constituting an auxiliary source of voltage practically in dependent of the load of said generator, the

armature of'said generator being connected in opposition to the armature of said aid dynamo and means- L I dynamo through said exciting winding, and i an electric motor for driving said enerator,

said electric motor being fed by sa' dynamo.

and provided with a fly wheel.

i 5 3. Arrangement for automatically regulating the voltage of a dynamo comprising a shunt ,winding and an auxiliary exciting winding for said dynamo, which winding is normally inoperative and only'rendere'd op- ,10 erative wlyan the voltage of said dynamo v vanes; a generator constituting an auxiliary source of voltage practicallyindependent of the load of said generator, the armature of said generator being connected in opposi- I 15 tion to the armature of said dynamo through said exciting winding, and an electric motor for driving said generator, said electric motor being fed by said dynamo and pro- .vided with a fly wheel and means for, con- 1 20 stantlly exciting said auxiliary generator.

4. rrangement for automatically regulating the voltage of a dynamo comprising.

a shunt windingand an auxiliary exciting winding for said dynamo, which winding is normally inoperative and only rendered 25- operative when the voltage of said dynamoh" varies; a generator constituting an auxiliary source of voltage practically independent I v of the load of said generator, the armature of said generatorbeingconnected in opposiac; tion to the armature of said dynamo through said exciting winding, and an electric motor for driving. said generator, said electric motor having shunt excitation and being fed by said dynamo and provided with 'a'85 fly wheel; and means for constantly excit-' in said auxiliary generator. lihe foregoing specificationsigned at Bar- Q men, Germany, this third day of December, 1913.

LUDWIG SCHON. [15s.] In presence '.of v

ALBER'r- UFER, JULIUs Fnsrm m. 

